NISCAIR Online Periodicals Repository Collection: IJC-B Vol.44B(11) [November 2005]

Kinetic study on lipase-catalyzed esterification in organic solvents

Sat, 29 Oct 2005 22:58:59 GMT

Title: Kinetic study on lipase-catalyzed esterification in organic solvents

Authors: Chowdary, G V; Prapulla, S G

Abstract: A twin inhibition is observed for the esterification reaction between ethanol and isovaleric acid using immobilized lipase from Rhizomucor miehei in hexane and in mixed solvent system. The observed bi-substrate inhibition pattern follows a Ping-Pong Bi-Bi mechanism with dead-end inhibition of enzyme by both the substrates. An increase in K_m value for alcohol in mixed solvent (0.645 M) than in hexane (0.256 M), indicates that the enhanced solvation of ethanol in mixed solvent results in lower degree of inhibition.

Page(s): 2322-2327

7-[(4-Substituted phenyl-piperazin-1-yl)-alkoxyl]-4-methylchromene-2-ones as potential atypical antipsychotics: Synthesis and pharmacological evaluation

Sat, 29 Oct 2005 22:58:59 GMT

Title: 7-[(4-Substituted phenyl-piperazin-1-yl)-alkoxyl]-4-methylchromene-2-ones as potential atypical antipsychotics: Synthesis and pharmacological evaluation

Authors: Shelke, S M; Sushilkumar; Sati, Nitin; Veer, V S; Bhosale, S H; Bodhankar, S L; Mahadik, K R; Kadam, S S

Abstract: 7-Hydroxy-4-methylchromene-2-one 1 when reacted respectively with 2-bromo-1-chloroethane and 3-bromo-1-chloropropane in acetonitrile and in the presence of anhydrous K₂CO₃ yields 7-alkoxy-4-methylchromene-2-ones 2a,b. Compounds 2a,b when refluxed with various arylpiperazines in toluene and in the presence of triethylamine yield the title compounds, 7-[(4-substituted phenyl-piperazin-1-yl)-alkoxyl]-4-methylchromen-2-ones 3a-j.Their atypical antipsychotic activity have been evaluated by their ability to inhibit apomorphine induced climbing behavior (D₂ antagonism) and to inhibit the 5–HTP induced head twitches in albino mice (5-HT_2A antagonism) alongwith catalepsy studies. All the compounds inhibit apomorphine induced climbing behavior and 5-HTP induced head twitches. The SAR studies reveal that methyl group in the phenyl ring of piperazine and the chain length (n=3) gives more dopaminergic and serotonergic antagonistic activity, while dichlorophenyl piperazines have less dopaminergic and serotonergic antagonistic activity. 3f and 3g have been found to have significant atypical behaviour.

Page(s): 2295-2300

A direct single step synthesis of 1,3-diaryl-4-cyanopyrazoles and their conversion to 1,3-diaryl-4-(4,6-diamino-1,3,5-triazin-2-yl)pyrazoles

Sat, 29 Oct 2005 22:58:59 GMT

Title: A direct single step synthesis of 1,3-diaryl-4-cyanopyrazoles and their conversion to 1,3-diaryl-4-(4,6-diamino-1,3,5-triazin-2-yl)pyrazoles

Authors: Reddy, G Jagath; Manjula, D; Rao, K Srinivasa

Abstract: A series of 1,3-diaryl-4-(4,6-diamino-1,3,5-triazin-2-yl)-pyrazoles 6a-g have been synthesized. 1,3-Diaryl-4-cyanopyrazoles 5a-i required as intermediates have been prepared in a single step from acetopheonone hydrazones 4a-i.

Page(s): 2412-2415

Synthesis and antidiabetic activity of 2-amino [5'(4-sulphonylbenzylidine)-2,4-thiazolidinedione]-7-chloro-6-fluorobenzothiazole

Sat, 29 Oct 2005 22:58:59 GMT

Title: Synthesis and antidiabetic activity of 2-amino [5'(4-sulphonylbenzylidine)-2,4-thiazolidinedione]-7-chloro-6-fluorobenzothiazole

Authors: Pattan, S R; Suresh, Ch; Pujar, V D; Reddy, V V K; Rasal, V P; Koti, B C

Abstract: A new series of 2-amino[5'(4-sulphonylbenzylidine)-2,4-thiazolidinedione]-7-chloro-6-fluorobenzothiazole were synthesized. The structures of the compounds were confirmed by UV-Vis, IR and NMR spectroscopy. The title compounds were screened for their antidiabetic activity on albino rats.

Page(s): 2404-2408